Systems and methods for making and using improved leads for electrical stimulation systems

ABSTRACT

A method for manufacturing a lead includes forming an elongated multi-lumen conductor guide defining a central stylet lumen and a plurality of conductor lumens arranged around the stylet lumen. The multi-lumen conductor guide is twisted to form at least one helical section where the plurality of conductor lumens each forms a helical pathway around the stylet lumen. Each of the helical pathways of the at least one helical section has a pitch that is no less than 0.04 turns per centimeter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application Ser. No. 61/494,247 filed on Jun. 7,2011, which is incorporated herein by reference.

FIELD

The invention is directed to the area of electrical stimulation systemsand methods of making and using the systems. The present invention isalso directed to electrical stimulation leads having leads with improvedflexibility and strain relief, as well as methods of making and usingthe leads and electrical stimulation systems.

BACKGROUND

Electrical Stimulation can be useful for treating a variety ofconditions. Deep brain stimulation can be useful for treating, forexample, Parkinson's disease, dystonia, essential tremor, chronic pain,Huntington's Disease, levodopa-induced dyskinesias and rigidity,bradykinesia, epilepsy and seizures, eating disorders, and mooddisorders. Typically, a lead with a stimulating electrode at or near atip of the lead provides the stimulation to target neurons in the brain.Magnetic resonance imaging (“MRI”) or computerized tomography (“CT”)scans can provide a starting point for determining where the stimulatingelectrode should be positioned to provide the desired stimulus to thetarget neurons.

After the lead is implanted into a patient's brain, electrical stimuluscurrent can be delivered through selected electrodes on the lead tostimulate target neurons in the brain. Typically, the electrodes areformed into rings disposed on a distal portion of the lead. The stimuluscurrent projects from the ring electrodes equally in every direction.Because of the ring shape of these electrodes, the stimulus currentcannot be directed to one or more specific positions around the ringelectrode (e.g., on one or more sides, or points, around the lead).Consequently, undirected stimulation may result in unwanted stimulationof neighboring neural tissue, potentially resulting in undesired sideeffects.

BRIEF SUMMARY

In one embodiment, a method for manufacturing a lead includes forming anelongated multi-lumen conductor guide defining a central stylet lumenand a plurality of conductor lumens arranged around the stylet lumen.The multi-lumen conductor guide is twisted to form at least one helicalsection where the plurality of conductor lumens each forms a helicalpathway around the stylet lumen. Each of the helical pathways of the atleast one helical section has a pitch that is no less than 0.04 turnsper centimeter. Optionally, heat is applied to the multi-lumen conductorguide to set the at least one helical section. Optionally, at least oneconductor is inserted into at least one of the plurality of conductorlumens.

In another embodiment, a lead for providing deep brain stimulationincludes a lead body having a distal end, a proximal end, and alongitudinal length. The lead body includes a multi-lumen conductorguide extending from the proximal end of the lead body to the distal endof the lead body. The multi-lumen conductor guide has an outer surfaceand defines a central stylet lumen configured and arranged for receivinga stylet and a plurality of conductor lumens disposed around the centralstylet lumen. Each conductor lumen is configured and arranged to receiveat least one conductor. The plurality of conductor lumens are completelyinset from the outer surface of the multi-lumen conductor guide. Atleast a portion of the multi-lumen conductor guide is twisted such thatthe multi-lumen conductor guide forms at least one helical section wherethe plurality of conductor lumens form helical pathways around thestylet lumen. Each of the helical pathways of the at least one helicalsection has a pitch that is no less than 0.04 turns per centimeter. Aplurality of electrodes are disposed on the distal end of the lead body.A plurality of lead terminals are disposed on the proximal end of thelead body. A plurality of conductors electrically couple at least one ofthe plurality of electrodes to at least one of the plurality of leadterminals. The plurality of conductors extend along the longitudinallength of the leady body within the plurality of conductor lumens.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified.

For a better understanding of the present invention, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, wherein:

FIG. 1 is a schematic side view of one embodiment of a brain stimulationsystem that includes a lead, a lead extension, and a control unit,according to the invention;

FIG. 2A is a schematic side view of one embodiment of a middle portionof a lead being held in position by a retaining feature;

FIG. 2B is a schematic side view of one embodiment of a middle portionof the lead of FIG. 2A being held in position by the retaining featureof FIG. 2A and a proximal end of the lead being bent in a firstdirection, the bending of the proximal end causing a correspondingdeflection of an opposing distal end of the lead in a second direction,opposite from the first direction;

FIG. 3 is a schematic side view of one embodiment of a middle portion ofthe lead of FIG. 1 held in position by the retaining feature of FIG. 2Aand a proximal end of the lead being bent in a first direction, thebending of the proximal end not causing any corresponding deflections ofan opposing distal end of the lead, according to the invention;

FIG. 4A is a transverse cross-sectional view of one embodiment of thelead of FIG. 1A, the lead including a multi-lumen conductor guide thatdefines a central stylet lumen and a plurality of conductor lumensarranged around the stylet lumen, according to the invention;

FIG. 4B is a transverse cross-sectional view of one embodiment ofconductors disposed in each of a plurality of conductor lumens of themulti-lumen conductor guide of FIG. 4A such that a different singleconductor is disposed in each of the conductor lumens, according to theinvention;

FIG. 5A is a transverse cross-sectional view of another embodiment ofthe multi-lumen conductor guide of FIG. 4A, the multi-lumen conductorguide defining a plurality of conductor lumens, each of the plurality ofconductor lumens receiving a plurality of conductors, according to theinvention;

FIG. 5B is a transverse cross-sectional view of yet another embodimentof the multi-lumen conductor guide of FIG. 4A, the multi-lumen conductorguide defining a plurality of conductor lumens, each of the plurality ofconductor lumens receiving a plurality of conductors, according to theinvention;

FIG. 5C is a transverse cross-sectional view of another embodiment ofthe multi-lumen conductor guide of FIG. 4A, the multi-lumen conductorguide defining a plurality of conductor lumens, each of the plurality ofconductor lumens receiving a plurality of conductors, according to theinvention;

FIG. 6A is a schematic side view of one embodiment of a helical sectionof the multi-lumen conductor guide of FIG. 4A, the helical sectiondefining a plurality of conductor lumens each defining a clockwisehelical pathway around at least a portion of a stylet lumen, accordingto the invention;

FIG. 6B is a schematic side view of another embodiment of a helicalsection of the multi-lumen conductor guide of FIG. 4A, the helicalsection defining a plurality of conductor lumens each defining acounter-clockwise helical pathway around at least a portion of a styletlumen, according to the invention;

FIG. 7A is a schematic side view of one embodiment of a portion of themulti-lumen conductor guide of FIG. 4A, the portion of the multi-lumenconductor guide defining the discrete helical section of either FIG. 6Aor FIG. 6B, according to the invention;

FIG. 7B is a schematic side view of one embodiment of a portion of themulti-lumen conductor guide of FIG. 4A, the portion of the multi-lumenconductor guide defining a plurality of the discrete helical sections ofeither FIG. 6A or FIG. 6B each separated from one another bysubstantially-straight sections, according to the invention;

FIG. 7C is a schematic side view of one embodiment of a portion of themulti-lumen conductor guide of FIG. 4A, the portion of the multi-lumenconductor guide defining a plurality of the discrete helical sections ofFIG. 6A and FIG. 6B abutting one another, according to the invention;

FIG. 7D is a schematic side view of one embodiment of a portion of themulti-lumen conductor guide of FIG. 4A, the portion of the multi-lumenconductor guide defining a plurality of the discrete helical sections ofFIG. 6A and FIG. 6B with alternating winding geometries, the helicalsections each separated from one another by substantially-straightsections, according to the invention; and

FIG. 7E is a schematic side view of one embodiment of a portion of themulti-lumen conductor guide of FIG. 4A, the portion of the multi-lumenconductor guide defining a plurality of the discrete helical sections ofFIG. 6A and FIG. 6B, some of the helical sections abutting one anotherand some of the helical sections separated from one another by asubstantially-straight section, according to the invention.

DETAILED DESCRIPTION

The invention is directed to the area of electrical stimulation systemsand methods of making and using the systems. The present invention isalso directed to electrical stimulation leads having leads with improvedflexibility and strain relief, as well as methods of making and usingthe leads and electrical stimulation systems.

A lead for deep brain stimulation may include stimulation electrodes,recording electrodes, or a combination of both. A practitioner maydetermine the position of the target neurons using the recordingelectrode(s) and then position the stimulation electrode(s) accordinglywithout removal of a recording lead and insertion of a stimulation lead.In some embodiments, the same electrodes can be used for both recordingand stimulation. In some embodiments, separate leads can be used; onewith recording electrodes which identify target neurons, and a secondlead with stimulation electrodes that replaces the first after targetneuron identification. A lead may include recording electrodes spacedaround the circumference of the lead to more precisely determine theposition of the target neurons. In at least some embodiments, the leadis rotatable so that the stimulation electrodes can be aligned with thetarget neurons after the neurons have been located using the recordingelectrodes.

Deep brain stimulation devices and leads are described in the art. See,for instance, U.S. Pat. No. 7,809,446 (“Devices and Methods For BrainStimulation”), U.S. Patent Application Publication No. 2010/0076535 A1(“Leads With Non-Circular-Shaped Distal Ends For Brain StimulationSystems and Methods of Making and Using”), U.S. Patent ApplicationPublication 2007/0150036 A1 (“Stimulator Leads and Methods For LeadFabrication”), U.S. patent application Ser. No. 12/177,823 (“Lead WithTransition and Methods of Manufacture and Use”), U.S. Patent ApplicationPublication No. 2009/0276021 A1 (“Electrodes For Stimulation Leads andMethods of Manufacture and Use”), U.S. Patent Application Ser. No.61/170,037 (“Deep Brain Stimulation Current Steering with SplitElectrodes”), U.S. Patent Application Ser. No. 61/022,953, U.S. PatentApplication Ser. No. 61/316,759, and U.S. Patent Application PublicationNo. 2009/0187222 A1. Each of these references is incorporated herein byreference in its respective entirety.

FIG. 1 illustrates one embodiment of an electrical stimulation system100 for brain stimulation. The electrical stimulation system 100includes a lead 110, a plurality of electrodes 125 disposed at leastpartially about a circumference of the lead 110, a plurality ofterminals 135, a lead extension 130 for connection of the electrodes 125to a control unit 160, and a stylet 140 for assisting in insertion andpositioning of the lead 110 in the patient's brain. It may beadvantageous to include the lead extensions 130 to prevent having toremove or replace the lead 110 if the proximal end of the lead 110 failsdue to fatigue (e.g., from flexing of the patient's neck, or the like).

The stylet 140 can be made of a rigid material. Examples of suitablematerials include tungsten, stainless steel, or plastic. The stylet 140may have a handle 150 to assist insertion into the lead 110, as well asrotation of the stylet 140 and lead 110. The lead extension 130 includesa connector 170 that fits over a proximal end of the lead 110,preferably after removal of the stylet 140.

The control unit 160 is typically an implantable pulse generator thatcan be implanted into a patient's body, for example, below the patient'sclavicle area. The pulse generator can have eight stimulation channelswhich may be independently programmable to control the magnitude of thecurrent stimulus from each channel. In some cases, the pulse generatormay have more than eight stimulation channels (e.g., 16-, 32-, or morestimulation channels). The control unit 160 may have one, two, three,four, or more connector ports, for receiving the plurality of terminals135 at the proximal end of the lead 110.

In one example of operation, access to the desired stimulation locationin the brain can be accomplished by drilling a hole in the patient'sskull or cranium with a cranial drill (commonly referred to as a “burr”or “bur”), and coagulating and incising the dura mater, or braincovering. The lead 110 can be inserted into the cranium and brain tissuewith the assistance of the stylet 140. The lead 110 can be guided to thetarget stimulation location within the brain using, for example, astereotactic frame and a microdrive motor system. In some embodiments,the microdrive motor system can be fully or partially automatic. Themicrodrive motor system may be configured to perform one or more thefollowing actions (alone or in combination): insert the lead 110,retract the lead 110, or rotate the lead 110.

In some embodiments, measurement devices coupled to the muscles or othertissues stimulated by the target neurons, or a unit responsive to thepatient or clinician, can be coupled to the control unit or microdrivemotor system. The measurement device, user, or clinician can indicate aresponse by the target muscles or other tissues to the stimulation orrecording electrode(s) to further identify the target neurons andfacilitate positioning of the stimulation electrode(s). For example, ifthe target neurons are directed to a muscle experiencing tremors, ameasurement device can be used to observe the muscle and indicatechanges in tremor frequency or amplitude in response to stimulation ofneurons. Alternatively, the patient or clinician may observe the muscleand provide feedback.

The lead 110 for deep brain stimulation can include stimulationelectrodes, recording electrodes, or both. In at least some embodiments,the lead 110 has a cross-sectional diameter of no more than 1.5 mm andmay be in the range of 1 to 1.5 mm. In at least some embodiments, thelead 110 is rotatable so that the stimulation electrodes can be alignedwith the target neurons after the neurons have been located using therecording electrodes. Stimulation electrodes may be disposed on thecircumference of the lead 110 to stimulate the target neurons.Stimulation electrodes may be ring-shaped or segmented.

The lead extension 130 typically couples the electrodes 125 to thecontrol unit 160 (which typically houses a pulse generator that supplieselectrical signals to the electrodes 125). Connectors of conventionallead extensions are typically disposed within patient tissue such thatthe connectors are disposed over the patient's skull and beneath orwithin the patient's scalp above one of the patient's ear.

It may be desirable for a lead to be flexible. As discussed above,during implantation a distal end of the lead is typically inserted intoa burr hole in the patient's scalp and positioned such that theelectrodes are disposed at a target stimulation location (e.g., the subthalamic nucleus, the globus pallidus interna, the ventral intermediatenucleus, or the like). A proximal end of the lead is typically coupledto a connector of a lead extension, disposed between the patient's skulland skin. In which case, the lead may make an approximately 90° bend inproximity to an outer portion of the burr hole through which the distalend of the lead is extended. Consequently, it may be desirable for thelead to be flexible enough to be able to make such a bend.

Bending one portion of the lead, however, might cause a correspondingundesired deflection at another portion of the lead. For example,bending in a proximal portion or a middle portion of the lead may causea corresponding undesired deflection at a distal end of the lead. Such adeflection may be caused, at least in part, by one or more conductors ofthe lead being held in tension, while one or more other conductors ofthe lead are held in compression. FIG. 2A is a schematic side view ofone embodiment of a lead 202 having a proximal end 204, a distal end206, and a middle portion 208. The middle portion 208 of the lead 202 isheld in position by a retaining feature 210 (e.g., a burr hole plug orcap, bone cement, one or more mini-plates, or the like). An axis 212 isshown passing through the portion of the lead 202 extending through theretaining feature 210. In FIG. 2A, the lead 202 is shown in a straightconfiguration, such that the entire lead 202 extends along the axis 212.

FIG. 2B is a schematic side view of one embodiment of the proximal end204 of the lead 202 bent in a first direction, away from the axis 212,as shown by arrow 214. As shown in FIG. 2B, bending of the proximal end204 of the lead 202 in a first direction causes a correspondingdeflection of the distal end 206 of the lead 202 in a second direction(opposite to the first direction), away from the axis 212, as shown byarrow 216.

Accordingly, it may be desirable for the lead to include a strain reliefthat prevents the bending of the lead proximal to a retaining feature(e.g., a burr hole plug or cap, bone cement, one or more mini-plates, orthe like) from causing a corresponding deflection of the lead distal tothe retaining feature. As herein described, the lead includes a leadbody with an elongated multi-lumen conductor guide configured andarranged to improve flexibility from conventional lead bodies and toprovide a strain relief that prevents bending of a first end of the leadfrom causing a corresponding deflection of an opposing end of the lead.

FIG. 3 is a schematic side view of one embodiment of the lead 110. Thelead 110 has a proximal end 302, a middle portion 304, and a distal end306. The middle portion 304 is held in a relatively stationary positionby the retaining feature 210 (e.g., a burr hole plug or cap, bonecement, one or more mini-plates, or the like). An axis 312 is shownpassing through the portion of the lead 110 extending through theretaining feature 210.

In FIG. 3, a portion of the lead 110 is shown bent in a first directionfrom the axis 312, as shown by arrow 514. It will be understood that thebend may occur at any suitable location along the length of the lead110. For example, in some cases the bend may occur distal to theterminals and proximal to the electrodes. As shown in FIG. 3, bending ofa portion of the lead 110 in a first direction does not cause acorresponding deflection of the distal end 306 of the lead 110.

The multi-lumen conductor guide described herein includes multipleconductor lumens arranged about a central stylet lumen. In at least somecases, the conductor lumens are arranged about the central stylet lumensuch that there are no other lumens extending along the multi-lumenconductor guide between the central stylet lumen and each of themultiple conductor lumens. The conductor lumens include at least onehelical section forming an enclosed pathway around at least a portion ofthe stylet lumen. In some cases, the conductor lumens are eachconfigured and arranged to receive a single conductor. In other cases,at least one of the conductor lumens is configured and arranged toreceive multiple conductors.

FIG. 4A is a transverse cross-sectional view of one embodiment of thelead 110. The lead 110 includes an elongated multi-lumen conductor guide402. The multi-lumen conductor guide 402 may extend an entirelongitudinal length of the lead 110 from the electrodes 125 to theterminals 135. As shown in FIG. 4A, the multi-lumen conductor guide 402defines a central stylet lumen 404 and a plurality of conductor lumens,such as conductor lumen 406. The conductor lumens can have any suitablecross-sectional shape (e.g., round, oval, rectangular, triangular, orthe like). In preferred embodiments, the conductor lumens have roundcross-sectional shapes.

In at least some embodiments, the plurality of conductor lumens 406 areencapsulated by the multi-lumen conductor guide 402 such that theconductor lumens 406 do not extend to an outer surface 408 of themulti-lumen conductor guide 402. In which case, when conductors (420 inFIG. 4B) are disposed in the conductor lumens 406, the conductors arenot exposed along the outer surface 408 of the multi-lumen conductorguide 402. The stylet lumen 404 and the plurality of conductor lumens406 can be arranged in any suitable manner. In preferred embodiments,the conductor lumens 406 are disposed in the multi-lumen conductor guide402 such that the conductor lumens 406 are peripheral to the styletlumen 404. In at least some cases, the lead 110 may include one or moreouter coatings of material 410 disposed over the outer surface 408 ofmulti-lumen conductor guide 402.

The stylet lumen 404 is configured and arranged to receive the stylet140. As discussed above, the stylet 140 can be used for assisting ininsertion and positioning of the lead 110 in the patient's brain. Theplurality of conductor lumens 406 are configured and arranged to receiveconductors, which electrically couple the electrodes 125 to theterminals 135. FIG. 4B is a transverse cross-sectional view of oneembodiment of conductors, such as conductor 420, disposed in theconductor lumens 406. In at least some cases, insulation 422 is disposedaround the conductors 420 to prevent short-circuiting of the conductors420.

In some cases, two or more conductors 420 can be disposed in one or moreof the conductor lumens 406. In at least some cases, the multi-lumenconductor guide 402 defines more than one conductor lumen 406, yetincludes fewer conductor lumens 406 than conductors 420. FIG. 5A-5C aretransverse cross-sectional views of three other embodiments of themulti-lumen conductor guide 402 defining the stylet lumen 404 and aplurality of conductor lumens, such as conductor lumen 406, where thenumber of conductor lumens 406 is less than the number of conductors420. Any suitable such configuration can be implemented. In FIGS. 5A-5C,the multi-lumen conductor guide 402 includes four conductor lumens 406and eight conductors 420. Each of the conductor lumens shown in FIG.5A-5C are configured and arranged to receive two conductors 420. Inother embodiments, at least one of the conductor lumens 406 can beconfigured and arranged to receive a different number of conductors thanat least one other of the conductor lumens 406.

When the conductor lumens 406 are configured and arranged to receive aplurality of conductors, the conductor lumens 406 can be arranged in anysuitable configuration. In FIGS. 5A-5C, the conductor lumens 406 eachhave a major axis 502 and a minor axis 504 that is perpendicular to themajor axis 502. In FIG. 5A, the conductor lumens 406 are configured andarranged such that the major axes 502 of the conductor lumens 406extends radially outward from the stylet lumen 404. In FIG. 5B, theconductor lumens 406 are configured and arranged such that the minoraxes 504 of the conductor lumens 406 extends radially outward from thestylet lumen 404. In FIG. 5C, the conductor lumens 406 are configuredand arranged such that neither the major axes 502 nor the minor axis 504of the conductor lumens 406 extend radially outward from the styletlumen 404.

FIGS. 6A and 6B are schematic side views of two embodiments of a helicalsection 602 of the multi-lumen conductor guide 402. The helical section602 can extend an entire length of the multi-lumen conductor guide 402,or one or more portions thereof. The multi-lumen conductor guide 402defines a plurality of conductor lumens, such as conductor lumen 406,twisted such that the individual conductor lumens 406 form helicalpathways around the stylet lumen 404. The conductor lumens 406 canextend in either clockwise or counter-clockwise directions. In FIG. 6A,the conductor lumens 406 are shown extending in a clockwise directionaround to the stylet lumen 404 (e.g., the conductor lumens 406 wraparound the stylet lumen in a clockwise direction when the multi-lumenconductor guide 402 is viewed from the distal end). In FIG. 6B, theconductor lumens 406 are shown extending in a counter-clockwisedirection around to the stylet lumen 404 (e.g., the conductor lumens 406wrap around the stylet lumen in a counter-clockwise direction when themulti-lumen conductor guide 402 is viewed from the distal end). Itshould be understood that the twisted lead embodiments of FIGS. 6A and6B may have transverse, cross-sections that are shown in FIGS. 4A, 4B,5A, 5B and 5C.

The conductor lumens 406 of the helical section 602 can be any suitablepitch. The pitch can be either constant or variable. In some cases, thepitch may be no less than 0.04 turns (i.e., 0.04 revolutions around acircumference of the stylet lumen 404) per cm. In some cases, the pitchmay be no less than 0.1 turns per cm. In some cases, the pitch may be noless than 0.2 turns per cm. In some cases, the pitch may be no less than0.25 turns per cm. In some cases, the pitch may be no greater than 0.8turns per cm.

In some cases, the pitch may be no less than 0.04 turns per cm and nogreater than 0.8 turns per cm. In some cases, the pitch may be no lessthan 0.1 turns per cm and no greater than 0.6 turns per cm. In somecases, the pitch may be no less than 0.1 turns per cm and no greaterthan 0.4 turns per cm. In some cases, the pitch may be no less than 0.2turns per cm and no greater than 0.4 turns per cm. In some cases, thepitch may be approximately 0.3 turns per cm.

In some cases, for a 40 cm section of the multi-lumen conductor guide402, each conductor lumen 406 of the helical section 602 forms at least2, 3, 4, or 5 turns. In some cases, for a 40 cm section of themulti-lumen conductor guide 402, each conductor lumen 406 of the helicalsection 602 forms no more than 25 turns.

In some cases, for a 40 cm section of the multi-lumen conductor guide402, each conductor lumen 406 of the helical section 602 forms no lessthan 2 turns and no more than 15 turns. In some cases, for a 40 cmsection of the multi-lumen conductor guide 402, each conductor lumen 406of the helical section 602 forms no less than 3 turns and no more than15 turns. In some cases, for a 40 cm section of the multi-lumenconductor guide 402, each conductor lumen 406 of the helical section 602forms no less than 4 turns and no more than 15 turns. In some cases, fora 40 cm section of the multi-lumen conductor guide 402, each conductorlumen 406 of the helical section 602 forms no less than 5 turns and nomore than 15 turns.

The conductor lumens 406 of the helical section 602 can be configuredinto any suitable arrangement (see e.g., FIGS. 4A-5C). The helicalsection 602 may include a single layer of conductor lumens 406 disposedover the stylet lumen 404. The conductor lumens 406 may be disposed overa single stylet lumen 404. In some cases, a single layer of conductorlumens 406 is disposed over a single stylet lumen 404.

In some cases, the helical section 602 extends along an entire length ofthe lead 110 between the electrodes (125 in FIG. 1) and the terminals(135 in FIG. 1). In other cases, the helical section 602 extends alongone or more discrete sections of the lead 110. When the helical section602 extends along one or more discrete sections of the lead 110, thediscrete helical section 602 can be any suitable length. In some cases,the discrete helical section 602 is at least 1 cm, 2 cm, 3 cm, 4 cm, 5cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, orlonger.

Turning to FIG. 7A, when the helical section 602 extends along adiscrete section of the multi-lumen conductor guide 402, the discretehelical section 602 can be disposed at any suitable location along thelength of the lead 110. In some cases, the discrete helical section 110may abut the electrodes (125 in FIG. 1), the terminals (135 in FIG. 1),or both. In other cases, the discrete helical section 602 can bedisposed somewhere along the length of the lead 110 between theelectrodes (125 in FIG. 1) and the terminals (135 in FIG. 1). When thediscrete helical section 602 is disposed somewhere along the length ofthe lead 110 between the electrodes (125 in FIG. 1) and the terminals(135 in FIG. 1), the remaining portions of the conductor lumens 406 canbe arranged into one or more other configurations, such as asubstantially-straight configuration (e.g., the conductor lumens 406extend less than one revolution about a circumference of the styletlumen 404 along a 20 cm length of the multi-lumen conductor guide 402).

FIG. 7A is a schematic side view of one embodiment of a portion of themulti-lumen conductor guide 402. The portion of the multi-lumenconductor guide 402 defines a discrete helical section 702 where each ofa plurality of conductor lumens defines a helical pathway around atleast a portion of a circumference of a stylet lumen. In FIG. 7A,substantially-straight sections 704 of the conductor lumens extend alongthe multi-lumen conductor guide 402 on either end of the discretehelical section 702. The helical section 702 and the flankingsubstantially-straight sections 704 can be any suitable lengths relativeto one another.

Turning to FIG. 7B, in some cases the multi-lumen conductor guideincludes a plurality of helical sections. When the lead includes aplurality of helical sections, the conductor lumens of the helicalsections can extend around the stylet lumen in either: a clockwisedirection; a counter-clockwise direction; or a combination of both,where at least one conductor lumen extends clockwise and at least oneconductor lumen that extends counter-clockwise around the circumferenceof the stylet lumen. In some cases, when the multi-lumen conductor guideincludes a plurality of helical sections, the helical sections each haveequal lengths. In other cases, when the lead includes a plurality ofhelical sections, at least one of the helical sections has a length thatis different from at least one other of the plurality of helicalsections.

FIG. 7B is a schematic side view of one embodiment of a portion of themulti-lumen conductor guide 402. The portion of the multi-lumenconductor guide 402 defines a plurality of the discrete helical sections702. In FIG. 7B, a substantially-straight section 704 is disposedbetween the discrete helical sections 702.

Turning to FIG. 7C, in some cases the multi-lumen conductor includes twoabutting discrete helical sections with conductors winding in oppositedirections. FIG. 7C is a schematic side view of one embodiment of aportion of the multi-lumen conductor guide 402. The portion of themulti-lumen conductor guide 402 defines a plurality of the discretehelical sections abutting one another. At least one of the helicalsections 702 a includes conductor lumens arranged in a clockwiseconfiguration, and at least one of the helical sections 702 b includesconductor lumens arranged in a counter-clockwise configuration.

Turning to FIG. 7D, in some cases the multi-lumen conductor includesmultiple discrete helical sections with conductors winding in oppositedirections, where the discrete helical sections are separated from oneanother by substantially-straight sections. FIG. 7D is a schematic sideview of one embodiment of a portion of the multi-lumen conductor guide402. The portion of the multi-lumen conductor guide 402 defines aplurality of discrete helical sections 702 a and 702 b. The helicalsections alternate between helical sections 702 a having conductorlumens arranged in a clockwise configuration, and helical sections 702 bhaving conductor lumens arranged in a counter-clockwise configuration. Asubstantially-straight section 704 separates each of the alternatinghelical sections 702 a and 702 b from one another.

FIG. 7E is a schematic side view of one embodiment of a portion of themulti-lumen conductor guide 402. The portion of the multi-lumenconductor guide 402 defines a plurality of discrete helical sections. Atleast some of the helical sections, such as helical sections 702 a and702 b ₁, abut one another. At least some of the helical sections, suchas helical sections 702 a and 702 b ₂, are separated from one another bya substantially-straight section 704. Additionally, at least one of thehelical sections, such as helical section 702 a includes conductorlumens arranged in a clockwise configuration, and at least one of thehelical sections, such as helical sections 702 b ₁ and 702 b ₂, includeconductor lumens arranged in a counter-clockwise configuration.

The multi-lumen conductor guide 402 can be formed as a single-piececomponent or as a multi-piece component. The multi-lumen conductor guide402 can be formed from any suitable material(s). For example, themulti-lumen conductor guide 402 can be formed from one or more thermosetpolymers, thermoplastic polymers (e.g., polyurethane, or the like),silicone, or the like or combinations thereof.

The multi-lumen conductor guide 402 can be formed in any suitablemanner. For example, the multi-lumen conductor guide 402 can beextruded. In some cases, the multi-lumen conductor guide 402 can betwisted as the multi-lumen conductor guide 402 is being extruded, orafter extrusion.

The multi-lumen conductor guide 402 can be formed such that theconductor lumens are in substantially-straight configurations. In somecases, the multi-lumen conductor guide 402 (or one or more portionsthereof) with the substantially-straight conductor-lumen configurationscan be twisted, as desired, to form one or more helical sections. Oncethe twisting is complete, the twisted multi-lumen conductor guide can beheated to set the helical section(s). In other cases, the multi-lumenconductor guide can be heated prior to twisting. In yet other cases, themulti-lumen conductor guide can be heated while being twisted. Theheating can be performed using at least one of: one or more transverseheating elements which heat one or more particular portions of themulti-lumen conductor guide at a time, or an elongated heating elementthat heats the entire multi-lumen conductor guide at once. In somecases, the lead can be heated from the inside out, for example, by usingone or more heating elements disposed in the stylet lumen.

In some cases, the conductors can be disposed in the conductor lumensprior to heating. In other cases, the conductor lumens can be emptyduring heating. In preferred embodiments, one or more mandrels aredisposed in at least some of the conductor lumens. It may beadvantageous to dispose mandrels in the conductor lumens prior toheating of the multi-lumen conductor guide to prevent the conductorlumens from collapsing during heating.

In at least some cases, a different mandrel is disposed in each of theconductor lumens during the heating process and then removed forinsertion of the conductors. Optionally, a mandrel can be disposed inthe stylet lumen. The mandrels disposed in the conductor lumens can haveany suitable diameter. In at least some cases, the mandrels havediameters that are smaller than diameters of the conductor lumens, yetlarger than diameters of the conductors. It may be advantageous to usemandrels with diameters that are smaller than diameters of the conductorlumens, yet larger than diameters of the conductors so that, during theheating process, the conductor lumens do not shrink to a size thatprevents (or makes difficult) insertion of the conductors into theconductor lumens after the multi-lumen conductor guide is twisted andheated, and the mandrels are removed.

The above specification, examples, and data provide a description of themanufacture and use of the composition of the invention. Since manyembodiments of the invention can be made without departing from thespirit and scope of the invention, the invention also resides in theclaims hereinafter appended.

What is claimed as new and desired to be protected by Letters Patent ofthe United States is:
 1. A lead for providing electrical stimulation,the lead comprising: a lead body having a distal end, proximal end, anda longitudinal length, the lead body comprising multi-lumen conductorguide extending from the proximal end of the lead body to the distal endof the lead body, the multi-lumen conductor guide having an outersurface and defining a central stylet lumen configured and arranged forreceiving a stylet and a plurality of conductor lumens disposed aroundthe central stylet lumen, each conductor lumen configured and arrangedto receive at least one conductor, wherein the plurality of conductorlumens are completely inset from the outer surface of the multi-lumenconductor guide, wherein at least a portion of the multi-lumen conductorguide is twisted such that the multi-lumen conductor guide forms atleast one helical section where the plurality of conductor lumens formhelical pathways around the stylet lumen, and wherein each of thehelical pathways of the at one helical section has a pitch that is noless than 0.04 turns per centimeter and no greater than 0.8 turns percentimeter; a plurality or electrodes disposed on the distal end of thelead body; a plurality of lead terminals disposed on the proximal end ofthe lead body; and a plurality of conductors electrically coupling atleast one of the plurality of electrodes to at least one of theplurality of lead terminals, wherein the plurality of conductors extendalong the longitudinal length of the leady body within the plurality ofconductor lumens.
 2. A method for manufacturing the lead of claim 1, themethod comprising: forming the multi-lumen conductor guide defining thecentral stylet lumen and the plurality of conductor lumens arrangedaround the stylet lumen; and twisting the multi-lumen conductor guide toform the at least one helical section where the plurality of conductorlumens each form the helical pathway wound the stylet lumen.
 3. Themethod of claim 2, further comprising applying heat to the multi-lumenconductor guide to set the at least one helical section.
 4. The methodof claim 3, further comprising inserting the plurality at conductorsinto the plurality of conductors lumens.
 5. The method of claim 4,further comprising inserting at least one mandrel into each of theplurality of conductor lumens prior to applying heat to the multi-lumenconductor guide.
 6. The method of claim 5, further comprising removingthe at least one mandrel from each of the plurality of conductor lumensprior to inserting the plurality conductors into the plurality ofconductor lumens.
 7. The method of claim 5, wherein inserting at leastone mandrel into each of the plurality of conductor lumens comprisesinserting at least one mandrel into each the plurality of conductorlumens with each of the at least one mandrels having a diameter that issmaller than a diameter of the conductor lumen into which the at leastone mandrel is disposed.
 8. The method of claim 5, wherein inserting atleast one mandrel into each of the plurality of conductor lumenscomprises inserting at least one mandrel into each of the plurality ofconductor lumens with each of the at least one mandrels having adiameter that is larger than a diameter of the at least one conductorinserted into the conductor lumen.
 9. The method of claim 2, whereintwisting the multi-lumen conductor guide to form helical pathways aroundthe stylet lumen comprises twisting the multi-lumen conductor guide toform helical pathways each having a pitch that is no less than 0.1 turnsper centimeter.
 10. The lead of claim 1, wherein each of the pluralityof conductor lumens is configured and arranged to receive a differentsingle conductor of the plurality of conductors.
 11. The lead of claim1, wherein each of the plurality of conductor lumens is configured andarranged to receive a plurality of conductors of the plurality ofconductors.
 12. The lead of claim 1, wherein the at least one helicalsection extends the entire longitudinal length of the lead body.
 13. Thelead of claim 1, wherein the at least one helical section extends lessthan the entire longitudinal length of the lead body.
 14. The lead ofclaim 1, wherein the multi-lumen conductor guide further comprises afirst straight section and the at least one helical section comprises afirst helical section and a second helical section disposed axiallyalong the multi-lumen conductor to guide from the first helical section,wherein the first straight section is disposed between the first helicalsection and the second helical section.
 15. The lead of claim 14,wherein the first helical section and the second helical section arewound in opposite directions along the longitudinal length of the leadbody from one another.
 16. The lead of claim 1, wherein the at least onehelical section has a constant pitch.
 17. The lead of claim 1, whereinthe at least one helical section has a variable pitch.
 18. The lead ofclaim 1, wherein each of the helical pathways of the at least onehelical section has a pitch that is no less than 0.1 turns percentimeter.
 19. An electrical stimulation system comprising: the lead ofclaim 1; a lead extension having a first end and an opposing second end,the lead extension comprising a plurality of lead extension terminalsdisposed on the second end of the lead extension; a connector disposedat the first end of the lead extension, the connector comprising aconnector housing defining a connector port, the connector portconfigured and arranged to receive the lead, a plurality of connectorcontacts disposed in the connector port, the connector contactsconfigured and arranged to electrically couple to the lead terminalswhen the lead is received by the connector housing, and a plurality ofconductors extending along a length of the lead extension, wherein eachof the conductors electrically couples at least one of the leadextension terminals to at least one of the plurality connector contacts;and a control unit coupleable to the second end of the lead extension,the control unit configured and arranged for providing stimulation tothe plurality of electrodes of the lead.